"The International Longshoremen's Association, the union representing the dockworkers, and the U.S. Maritime Alliance, a group of shippers and port operators, are deadlocked over an employment contract that expired at the end of September but has been extended. The union has said that if the contract expires without a resolution, it could call a strike a day later.

"The White House had no comment on whether the president would consider invoking federal law to impose a cooling off period. Florida Governor Rick Scott, a Republican, asked President Obama to invoke the 1947 Taft-Hartley Act, which allows the president to prevent or interrupt a work stoppage.

"In just a few days, a walkout by thousands of dockworkers could bring commerce to a near standstill at every major port from Boston to Houston, potentially delivering a big blow to retailers and manufacturers still struggling to find their footing in a weak economy.

"More than 14,000 longshoremen are threatening to go on strike Sunday -- a wide-ranging work stoppage that would immediately close cargo ports on the East Coast and the Gulf of Mexico to container ships.

"The 15 ports involved in the labor dispute move more than 100 million tons of goods each year, or about 40 percent of the nation's containerized cargo traffic. Losing them to a shutdown, even for a few days, could cost the economy billions of dollars."